Said de vilbiss



I. A. DE VILBISS AND H. L. MILLER.

INIENSIHER ron PARK PLuGs.

APPLICATION FILiD APR- 5| 1919.

Patented Apr. 6, 1920.

nn'rrnn srairns PATENT FFICE.

JOHN A. DE VILBISS AND HENRY L. lVlILLEity OF ST. LOUIS, MISSOURI; SAID DE VILBISS ASSIGNOR OF HIS RIGHT TO GEORGE F. ERNST, OF ST. LOUIS, MISSOURI.

i INTENSIFIER FOR SPARK-PLUGS.

Application led April 5, i919.

To all whom t may concern:

Be it known that we, JOHN A. DE Vriiniss and IInNnr L. MILLER, citizens of the United Sta-tes, residing in the city of StIiouis, State of Missouri, have invented a certain new and useful Improvement in Intensiliers for Spark-Plugs, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

rI`his invention relates to intensifiers for spark plugs of internal combustion engines.

The main object of our invention is to provide Van intensifier that can be placed directly on top of the spark plug with which it is used, thereby `eliminating all separate attaching devices, and also having the intensiier in such a position that it will be subjected to the least vibration when the engine is in operation.

Another object is to provide an intensifier that is small and compact, neat in appearance and which can be manufactured and sold at a low cost.

Still another object is to provide an intensifier that is provided with integral means in the interior thereof for attachment to a spark plug. Other objects and desirable features of our invention will be hereinafter pointed out.

Figure l of the drawings is a perspective view of an intensifier constructed in accordance with our invention, showing the same attached to a spark plug.

Fig. 2 is a vertical sectional view of said intensifier; and

nig. 3 is a detail view, illustrating a different method from that shown in Figs. l and 2 for attaching the intensifier to the spark plug` Referring to Figs. l and 2 of the drawings which illustrate the preferred form of our invention, A designates the body portion of our improved intensifier which is' preferably cylindrical and formed of fiber or other suitable insulating material, and B and B designate cap pieces which inclose the upper and lower ends of said body portion, respectively, said cap pieces preferably having their open ends turned or spun into slight grooves in said body portion, as shown at l in Fig. 2. Internally screw-threaded tubes 2 and 3 extend inwardly from the center of Specification of Letters Patent.

Patented Apr. 6, 1920.4

Serial No. 287,879.

-said cap pieces B and B', respectively, said tubes being preferably, but not necessarily, an integral part of said cap pieces, as shown c early in Fig. The tube 3 on the lower cap piece B is provided with internal screw threads for the reception of the usual threaded stem #l of a spark plug C, said tube being of sufiicient length that when it is in position on the plug, the stem a will not project above the upper edge thereof. A rod 5 is threaded into the tube 2 of the upper cap piece B, the lower end of said rod being spaced away from the upper end of the tube 3, so as to provide a gap a across which the electrical spark of the intensifier jumps when the device .is in operation. The rod 5, being threaded into the tube 2, is adjustable vertically so as to vary the size of the spark gap :c to suit different engine conditions, and a lock nut 6 is provided to hold said rod in adjusted position, the upper end of said rod extending upwardly beyond said cap piece to form a binding post for the usual electrical terminal (not shown).

In order to see the lower end of the rod 5 and the upper end of the tube 3 and to enable the gap a formed therebetween to be accurately adjusted, we provide a pair of oppositelysdisposed sight openings 7 in the body portion A at a point substantially in alinement with said gap a2, and a transparent member 8, preferably a sleeve formed of mica or other suitable material is placed over the inside of said openings so as to protect the interior of the intensifier.

In the majority of instances, the intensifier can be screwed directly onto the usual threaded stem l of a spark plug, thereby eliminating separate connecting devices vand relieving the intensifier of any undue vibration which would occur if the intensifier were placed at one side of the plug` and connected thereto by a thin brass terminal, as is the usual practice.

In some f cases an engine is so designed that the intensier cannot be placed in a vertical position on the plug, and also in some instances the diameter of the stein l of the spark plug may be slightly dilferent from the diameter of the threads in the tube 3, In such cases we provide an adapter D which consists of a threaded stem 9 that fits in the tube 3 and an eye 10 that slips over the stein et of the spark plug, a nut ll being screwed onto said stein to hold said adapter in position. The intensifier is then supported in a substantially horizontal position at one side of the spark plug, as shown clearly in Fig. 3.

lt will be obvious that when the device is in operative position on a spark plug and the usual electrical connections are applied, that the electric current passing through the rod 5 will be forced to juinp the gap before j un'iping the usual gap between the contacts c of the spark plug, thus greatly intensifying the spark produced at. said contaets.

An 'intensifier of the construction above described is small, light and coinpact and comprises only a few simple parts which can be manufactured and assembled cheaply and sold at a comparatively low price. By placing' the intensifier directly' on the stein l of the spark plug, vibration is reduced to a ininiinuni and the life of the intensifier is consequently greatly prolonged. The spark gap ai of the intensifier can be easily varied to obtain the lbest results, while the engine isin operation, by turning the rod 5 in one direction or the other and observing the result through the sight openings provided in the body portion.

Having thus described our invention,

what we elaini and desire to secure by Letters Patent, is:

l. An intensifier for spark plugs, coinprising a body portion provided on its interior with a spark gap, and a threaded tube in said body portion, the upper end of which forins one side of said gap and the lower end of which is adapted to be threaded directly onto a spark plug.

2. An intensifier for spark plugs, cornprising a body portion of insulating material, cap pieces at each end thereof having inwardly-projecting, internally-threaded eX- tensions, and an adjustable rod in one of said extensions having its lower end spaced away froin the upper end of the other eX- tension so as to forni a gap therebetween.

3. An intensifier for spark plugs, consisting a body portion comprising a sleeve of insulating material, cap pieces on each end of` said sleeve, internallythreaded tubes extending inwardly from the center of each of said cap pieces, an adjustable rod mounted in one of said tubes, ineans for locking said rod in adjusted position, sight openings in said body portion substantially in alinement with the lower end of said rod, and a transparent cover for said openings.

JOHN A. DE VILBISS. HENRY L. MILLER. 

